Lorcaserin of Formula (I) is chemically known as (R)-8-chloro1-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride. Lorcaserin hydrochloride of Formula (I) is an agonist of the 5-HT2C receptor and shows effectiveness at reducing obesity in animal models and humans. Further, 5-HT2C receptor is recognized as a well-accepted receptor target for the treatment of obesity, psychiatric, and other disorders. Lorcaserin hydrochloride of Formula (I) is approved as anti-obesity agent and is marketed under the brand name Belviq in USA.

U.S. Pat. No. 6,953,787 discloses Lorcaserin or a pharmaceutically acceptable salt, solvate or hydrate thereof. US '787 also discloses the process for the preparation of Lorcaserin or a pharmaceutically acceptable salt comprising the step of deprotecting N-trifluoroacetyl-8-chloro-1-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine or a pharmaceutically acceptable salt to form Lorcaserin or a pharmaceutically acceptable salt.
U.S. Pat. No. 8,168,624 disclose crystalline forms of Lorcaserin hydrochloride, namely three crystalline forms of Lorcaserin hydrochloride, individually designated as Form I, Form II and Form III (hemihydrate) of Lorcaserin hydrochloride. Form I and Form II of Lorcaserin hydrochloride are anhydrous, hygroscopic forms, both of which readily convert to Form III (hemihydrate) of Lorcaserin hydrochloride of Formula (Ia), upon exposure to moisture.
US '624 also discloses a process for the preparation of Lorcaserin hydrochloride hemihydrate of Formula (Ia) which comprises mixing Lorcaserin hydrochloride of Formula (I) with a crystallizing solvent containing water and inducing precipitation of the Lorcaserin hydrochloride hemihydrate of Formula (Ia) from the crystallizing solvent.
The process is shown in Scheme-I as given below:

US 2013/0158013 discloses a crystalline Form IV of Lorcaserin hydrochloride, is an anhydrous polymorph. Further US '013 disclose that Lorcaserin hydrochloride crystalline Form IV is the most stable of anhydrous polymorphs at ambient temperature.
US '013 also disclose a process for the preparation of Lorcaserin hydrochloride hemihydrate (Form III), comprising slurrying a first mixture comprising Lorcaserin hydrochloride salt Form IV and a first solvent to form (R)-Lorcaserin HCl hemihydrate (Form III).
However, the above processes suffer from low yield and low purity of Lorcaserin HCl hemihydrate (Form III). Therefore, these processes of making Lorcaserin HCl hemihydrate (Form III) are not commercially feasible.
However, there is always a need for an alternative process, which for example, involves use of reagents/solvents that are less expensive and easier to handle, consume smaller amounts of solvents, and provide a higher yield of product with higher purity.
Hence, there is a need to develop cost effective and commercially viable process for the preparation of Lorcaserin hydrochloride of Formula (I).
The present invention directed towards a process for the preparation of crystalline Lorcaserin hydrochloride hemihydrate of Formula (Ia) with high purity and high yield.